1. Field of the Invention
The present invention relates to display technology field, and more particularly to a vacuum evaporation apparatus and an evaporation method.
2. Description of Related Art
The organic light emitting display panel is a self-luminous display panel, which having advantages of solid-state, thin, non-limitation of viewing angle, rapid response, room temperature operation, easy to realize a flexible display and 3D display, etc., and it is recognized as the mainstream technology of the next generation display.
In the manufacturing process of the organic light emitting panel, it requires to form an organic light emitting layer on the substrate, that is, forming an organic light emitting diode (OLED) on the substrate. Currently, the forming of the organic light emitting diode is mainly used the method of heating evaporation coating. With reference to FIG. 1, it is the vacuum evaporation apparatus in the prior art, and comprising a vacuum chamber, an evaporation source 50 disposed inside the vacuum chamber, and a cooling plate 210 located above the evaporation source 50.
Wherein, the evaporation source 50 includes a material container 510 and a heating source 520 disposed at the outside of the material container 510. In the manufacturing of the organic light emitting panel, sequentially disposing the substrate 220 and the mask 230 below the cooling plate 210, a side of the substrate 220 waiting to deposit the evaporation material face toward the evaporation source 50, wherein, the cooling plate 210 is used for fixing the substrate 220 and the mask 230, and also used for cooling the substrate 220.
The heating source 520 heats the material container 510, the evaporation material 530 inside the material container 510 is heated to become a material vapor and it flows into the vacuum chamber. The material vapor flow through the opening area of the mask 230, and it is cooled on the substrate 220 to form the organic light emitting layer. However, in the evaporation process, the mask 230 will deform by the influence of the gravity, resulting in a gap between the mask 230 and the substrate 220. The material vapor will deposit on an area other than the opening area of the substrate 23, and then, it will impact the color purity of light of the OLED display panel, which decreasing the display effect of the OLED display panel. Especially for a large-size display panel, the larger the size of the display panel, the deformation of mask 230 influenced by the gravity is more obvious such that the display effect is worse.